Orlando, FL.

I planted 5 podocarpus plants a month or two ago and I'm starting to notice a couple stalks have died and turned brown. I don't know the type of podocarpus, but it's the same type of plant they sell at Lowes or Home Depot. The plants look well fed and I planted them in good soil, but I notice some of the new growth is started to shrivel. Is this a water issue or are they not getting nutrients? What can I do to get them to bounce back before they all die?